Radioactive fluoride wastes are generated during the operation of molten salt reactors(MSRs) and reprocessing of their spent fuel.Immobilization of these wastes in borosilicate glass is not feasible because of the ver...Radioactive fluoride wastes are generated during the operation of molten salt reactors(MSRs) and reprocessing of their spent fuel.Immobilization of these wastes in borosilicate glass is not feasible because of the very low solubility of fluorides in this host.Alternative candidates are thus an active topic of research including phosphatebased glasses,crystalline ceramics,and hybrid glass-ceramic systems.In this study,mixed fluorides were employed as simulated MSRs waste and incorporated into sodium aluminophosphate glass to obtain phosphate-based waste form.These waste forms were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.Leaching tests were performed in deionized water using the product consistency test A method.This study demonstrates that up to 20 mol%of simulated radioactive waste can be introduced into the NaA1 P glass matrix,and the chemical durability is much better than that of borosilicate.The addition of Fe_2O_3 in the NaAlP glass matrix results in increases of the chemical durability at the expense of fluoride loading(to 6.4 mol%).Phosphate glass vitrification of radioactive waste containing fluorides is a potential method to treat and dispose of MSR wastes.展开更多
Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^(4+)). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects ...Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^(4+)). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions(pH=10) were smaller than those in acid solutions(p H=4). At a certain p H value, the normalized release rate of Ce(LR Ce) increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_(Ce) were below 10^(–5)g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.展开更多
文摘Radioactive fluoride wastes are generated during the operation of molten salt reactors(MSRs) and reprocessing of their spent fuel.Immobilization of these wastes in borosilicate glass is not feasible because of the very low solubility of fluorides in this host.Alternative candidates are thus an active topic of research including phosphatebased glasses,crystalline ceramics,and hybrid glass-ceramic systems.In this study,mixed fluorides were employed as simulated MSRs waste and incorporated into sodium aluminophosphate glass to obtain phosphate-based waste form.These waste forms were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.Leaching tests were performed in deionized water using the product consistency test A method.This study demonstrates that up to 20 mol%of simulated radioactive waste can be introduced into the NaA1 P glass matrix,and the chemical durability is much better than that of borosilicate.The addition of Fe_2O_3 in the NaAlP glass matrix results in increases of the chemical durability at the expense of fluoride loading(to 6.4 mol%).Phosphate glass vitrification of radioactive waste containing fluorides is a potential method to treat and dispose of MSR wastes.
基金Project supported by the National Natural Science Foundation of China(21507105,41302029)Thousand Youth Talents Plan(Y42H831301)+3 种基金Key Project of Sichuan Education Department(15ZB0116)Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk10)the Doctor Foundation in Southwest University of Science and Technology(10zx7126)Sichuan’s Training Program of Innovation and Entrepreneurship for Undergraduate(201610619039)
文摘Zircon was employed to immobilize simulated tetravalentactinide nuclide(Ce^(4+)). Zr_(1–x)Ce_xSiO_4(0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of p H and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions(pH=10) were smaller than those in acid solutions(p H=4). At a certain p H value, the normalized release rate of Ce(LR Ce) increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the p H and the temperature had slight impact on the leaching of Ce element. Moreover, the LR_(Ce) were below 10^(–5)g/m^2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.
